Investigation of blood coagulation and hemophilia with a study of the hemophilias in dogs and man from the genetic, biochemical and pathologic points of view, and the study of some of the basic reactions of platelets with plasma in the development of platelet aggregates. Specific areas of investigation include studies of: a) Genetics and pathophysiology of canine hemophilia A and B; b) purification of plasma antihemophilic factor (AHF) (Factor VIII) with the aim of obtaining a material pure enough to proceed with physico-chemical characterization; c) development, distribution and neutralization of the inhibitors to AFH induced in normal and hemophilic dogs with purified AHF preparations of bovine, porcine, and human origin; d) histogenesis and ultrastructure of the joint lesions of canine hemophilia; e) role of plasma proteins in platelet adhesion and aggregation.